In many situations it is desired to allow a shaft or other rotating member to rotate in a forward rotary direction but to prevent any substantial movement in a reverse rotary direction. For example, postage meters often use a rotating drive shaft to rotate the print head during each metering cycle. For security, one of the requirements for postage meters is that the drive shaft cannot be allowed to be forced to move in a reverse direction. One way to prevent the reversal has been to mount a ratchet wheel on the drive shaft and have spring fingers engage the toothed outer surfaces of the ratchet wheel during rotation. However, it has been found that in some situations such spring fingers have been subject to excessive wear and fracture during use.